A process for obtaining of the silicon, silicon carbide and the germanium extremely pure

摘要

PICT:0934673/III/1 A process for producing the semi-conductor material silicon, silicon carbide and germanium comprising depositing said material from a compound thereof, by chemical reaction in the gas phase and in the presence of a carrier gas, on to one or more longitudinally extending carrier bodies disposed in a reaction vessel and made of said material, is characterized by heating said carrier bodies prior to reaction whilst passing a stream of carrier gas through said reaction vessel so that the heat emitted by said carrier bodies is sufficient to heat the wall to a minimum temperature of 300 DEG C., the deposition reaction being thereafter carried out with the wall maintained at or above said minimum temperature. By this means deposition of semi-conductor on the inner wall of the reaction vessel at the beginning of the reaction is avoided, and subsequent deposition is avoided if the ratio of semi-conductor compound to carrier gas does not substantially exceed 0,2. Silicochloroform and silicon tetrachloride may be used for the deposition of silicon, monomethyl-trichlorosilane for deposition of silicon carbide, and germanium tetrachloride for deposition of gemanium. Hydrogen may be used both as reaction gas and carrier gas, as may other hydrocarbons, for example methane. The carrier bodies may be heated by passing an electric current therethrough, or by induction heating or radiation heating. Apparatus illustrated in the Figure comprises reaction cylinder 11, which may be glass or quartz, with metal closure plate 12 on which are mounted carrier rods 10 interconnected by bridge 9 and terminating in holder 13 connected to voltage source 16. Carrier gas is introduced from cylinder 2 through nozzle 7 and removed through discharge tube 8, after which the carrier rods are heated to about 1200 DEG C. and reaction mixture introduced. Specifications 853,729 and 861,135 are referred to.